AIM: To assess the utility and safety of single-operator cholangiopancreatoscopy(SOCPS) using the Spy Glass system in widespread clinical application for biliary and pancreatic diseases.METHODS: This study was a prospective case series conducted in 20 referral centers in Japan. There were 148 patients who underwent SOCPS; 124 for biliary diseases and 24 for pancreatic diseases. The attempted interventions were SOCPS examination, SOCPS-directed tissue sampling, and therapy for stone removal, among others. The main outcomes were related to the procedure success rate in terms of visualizing the target lesions, SOCPS-directed adequate tissue sampling, and complete stone removal. RESULTS: A total of 148 patients were enrolled for the diagnosis of indeterminate biliary and pancreatic lesions or treatment of biliary and pancreatic disease. The overall procedure success rate of visualizing the target lesions was 91.2%(135/148). The overall procedural success rates of visualizing the target lesions of diagnostic SOCPS in the bile duct and pancreatic duct were 95.5%(84/89) and 88.2%(15/17), respectively. Diagnosis: the overall adequate tissue for histologic examination was secured in 81.4% of the 86 patients who underwent biopsy under SOCPS(bile duct, 60/75, 80.0%; pancreatic duct, 10/11, 90.9%). The accuracy of histologic diagnosis using SOCPS-directed biopsies in indeterminate bile duct lesions was 70.7%(53/75). In the pancreatic duct, the accuracy of SOCPS visual impression of intraductal papillary mucinous neoplasm was 87.5%(14/16). Stone therapy: complete biliary and pancreatic stone clearance combined with SOCPS-directed stone therapy using electrohydraulic lithotripsy or laser lithotripsy was achieved in 74.2%(23/31) and 42.9%(3/7) of the patients, respectively. Others: SOCPS using the Spy Glass system was used in cannulation of the cystic duct in two patients and for passing across the obstructed self-expandable metallic stent for a malignant biliary stricture in two patients. All procedures were successful in both SOCPS-guided therapies. The incidence of procedure-related adverse events was 5.4%(8/148). CONCLUSION: SOCPS with direct visualization and biopsy for diagnosis and SOCPS-directed therapy for biliary and pancreatic diseases can be safely performed with a high success rate. AIM: To assess the utility and safety of single-operator cholangiopancreatoscopy (SOCPS) using the Spy Glass system in widespread clinical application for biliary and pancreatic diseases.METHODS: This study was a prospective case series conducted in 20 referral centers in Japan. There were 148 attempted interventions were SOCPS examination, SOCPS-directed tissue sampling, and therapy for stone removal, among others. The main outcomes were related to the procedure success rate in terms of of visualizing the target lesions, SOCPS-directed adequate tissue sampling, and complete stone removal. RESULTS: A total of 148 patients were enrolled for the diagnosis of indeterminate biliary and pancreatic lesions or treatment of biliary and pancreatic disease. The overall procedure success rate of visualizing the target lesions was 91.2% (135/148). The overall procedural success rates of visualizing the target les ions of diagnostic SOCPS in the bile duct and pancreatic duct were 95.5% (84/89) and 88.2% (15/17), respectively. Diagnosis: the overall adequate tissue for histologic examination was secured in 81.4% of the 86 patients who underwent The accuracy of histologic diagnosis using SOCPS-directed biopsies in indeterminate bile duct lesions was 70.7% (53/75). In the pancreatic duct, the accuracy of SOCPS visual impression of intraductal papillary mucinous neoplasm was 87.5% (14/16). Stone therapy: complete biliary and pancreatic stone clearance combined with SOCPS-directed stone therapy using electrohydraulic lithotripsy or laser lithotripsy was achieved in 74.2 % (23/31) and 42.9% (3/7) of the patients, respectively. Respectively: SOCPS using the Spy Glass system was used in cannulation of the cystic duct in two patients and for passing across the obstructed self-expandable metallic stent for a malignant biliary stricture in twoAll procedures were successful in both SOCPS-guided therapies. The incidence of procedure-related adverse events was 5.4% (8/148). CONCLUSION: SOCPS with direct visualization and biopsy for diagnosis and SOCPS-directed therapy for biliary and pancreatic diseases can be safely performed with a high success rate.